Electric connector for the motor of a hermetic compressor

ABSTRACT

An electric connector for the motor of a hermatic compressor, comprising an electric insulating body seated against the stack of lamination ( 6 ) of the stator of the electric motor, and carrying a plurality of binding posts ( 22 ), which receive and affix respective wires from the coil windings ( 7 ) of said stator of the electric motor; contact terminals, eletrically connected to the binding posts ( 22 ), and which will be connected to the hermetic compressor, by respective conductors ( 30 ); and at least one fixation means ( 23 ), which is fitted and immobilized in a retaining bore ( 11 ) provided in the stack of lamination ( 6 ) of the stator.

CROSS REFERENCE TO PRIOR APPLICATIONS

This is a U.S. national phase application under 35 U.S.C. §371 ofInternational Patent Application No. PCT/BR01/00152 filed Dec. 11, 2001.The International Application was published in English on Jun. 20, 2002as International Publication No. WO 02/49186 A2 under PCT Article 21(2).

FIELD OF THE INVENTION

The present invention refers to an electric connector for the electricmotor of a hermetic compressor of the type used in refrigerationappliances, such as refrigerators, freezers, water fountains, etc., forconnecting inside the hermetic shell of the compressor the coils of theelectrical motor to a power inlet plug provided in the shell of thecompressor.

BACKGROUND OF THE INVENTION

The motor of a hermetic compressor usually comprises, mounted inside itshermetic shell, a rotor and a stator, the latter being formed by a maincoil and a secondary coil, said motor being fed by an electric currentfrom a power source external to said hermetic shell, by connecting anappropriate wiring to a power inlet plug, mounted externally to thehermetic shell and which is electrically connected to the stator of theelectric motor.

In a known construction, in order to connect the stator to the powerinlet plug of the hermetic shell through the interior of the latter,some copper wires of the stator, generally three, are connected to acable by clamping a metallic piece, joining each copper wire to thecable, which is then connected to the shell. After clamping the twoparts together, for each wire, the formed assembly receives a thermalretractible insulating cover, which protects said connection thusobtained. After the connection, the whole assembly is positioned insidethe coils that form the motor.

This construction presents some disadvantages, such as difficultautomation, for example in the clamping steps, which also results in lowquality of the obtained electric connections, with a high number ofdefects and rejections, for example due to low efficiency of theintended connection and to failures in the process for obtaining saidconnection.

In another known construction, the electric connections of the motor tothe shell of the compressor occur through an electric connection device,which receives each copper wire from the motor coils to be electricallyconnected to the shell of the compressor, and which lodges each of saidwires in a respective contact cradle. While this solution allows forautomation and improves the quality of the electric connections betweenthe motor and the hermetic shell of the compressor, as compared to theelectric connections obtained by clamping, the known constructions foran electric connection device present deficiencies in relation to theform of retaining said devices inside the hermetic shell of thecompressor.

In one of the known solutions for affixing the electric connectiondevice inside the hermetic shell of the compressor, one of the partswhich forms said device and which is provided with teeth is affixed, byinterference, in the stator of the electric motor. In another knownsolution, the part to be affixed to the stator is provided with flanges,which are fitted into a portion of the stator, before fastening thereof.

In the first fixation option, the disadvantages reside in the fact thatthe fixing means is easily broken, due to aging of the material,generally plastic, and the possibility of occurring relative movementsbetween the electric connection device and the stator wire, which canlead, with time, to material fatigue.

Moreover, this construction allows the occurrence of undesiredvibrations in the connection. In the second fixation option, thedisadvantages result from the fact that, for each flange of the electricconnection device to be fastened to the stator, there is loss of afastening point thereof. In the known fixations, three fastening pointsof the stator are lost with this process.

SUMMARY OF THE INVENTION

Thus, it is an object of the present invention to provide an electricconnector for the motor of a hermetic compressor, which allows a safeand strong fixation thereof to said electric motor, without thedisadvantages of occurring ruptures or fatigue, or impairing thefastening of the stator.

It is a further object of the present invention to provide an electricconnector with the characteristics mentioned above, which allowsobtaining the desired electric connection in a substantially automatizedform.

These and other objects are attained by an electric connector for themotor of a hermetic compressor, said motor being mounted inside ahermetic shell and comprising a stator formed by a stack of overlappedlaminations lodging coil windings, said shell carrying a power inletplug to be connected to a current supply source, said electric connectorcomprising an electric insulating body, seated against the stack oflaminations of the stator and carrying: a plurality of binding posts,which receive and affix respective wires of the coil windings; contactterminals, electrically connected to the binding posts and which will beconnected to the power inlet plug of the shell by respective conductors;and at least one fixing means, which is fitted and immobilized in aretaining bore provided in the stack of laminations of the stator.

BRIEF DESCRIPTION DRAWINGS

The invention will be described below, with reference to the encloseddrawings, in which:

FIG. 1 shows, schematically, a longitudinal diametrical sectional viewof a hermetic compressor of the reciprocating type with a verticalshaft, presenting an electric connection between the motor and the shellof the compressor, using the electric connector of the presentinvention;

FIG. 2 shows, schematically, an upper view of the stator of the electricmotor, the windings of said stator and the wires for electricallyconnecting the windings being prepared for connecting the hermetic shellof the compressor, according to the prior art;

FIG. 3 shows, schematically, a lower view of the stator of the electricmotor, presenting the stator, the windings of said stator and the wiresfor electrically connecting the windings being prepared for connectingthe hermetic shell of the compressor, using the electric connection ofthe present invention;

FIG. 4 shows, schematically, a front view of the electric connector ofthe present invention, before its assembly to the stator;

FIG. 5 shows, schematically, a lateral longitudinal sectional view ofpart of the electric connector of the present invention; and

FIG. 6 shows, schematically, and in an upper view, the electricconnector of the present invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

The present invention will be described now in relation to areciprocating compressor used in refrigeration systems and of the typehaving a vertical shaft (FIG. 1), comprising a hermetic shell 1, insidewhich is suspended, in an appropriate manner, for example by springs, amotor-compressor assembly formed by a cylinder block 2, to which isaffixed an electric motor, whose rotor 3 is fixedly mounted to avertical crankshaft 4 supported on a main bearing, which is machined inthe cylinder block 2.

The crankshaft 4 sustains, at the lower portion thereof, a pump rotor,which carries oil from an oil sump 5 to the parts of the cylinder block2 requiring lubrication during the operation of the compressor.

The electric motor of the compressor comprises, besides the rotor 3, astator formed by a stack of laminations 6, which are metallic and inoverlapped alignment, so as to define axial housings to receive coilwindings 7 from the electric motor.

The electric motor is fed with current from an appropriate and notillustrated current source, by electrically connecting said currentsource with a power inlet plug 8, carried by the shell 1 and which iselectrically connected to the electric motor of the compressor.

According to the present invention, the stator carries, fixedly seatedagainst its stack of laminations 6, for example in one of the endlaminations thereof, an electric connector 20, to be described ahead andwhich, by means of conductors 30, electrically connects the electricmotor of the compressor to the power inlet plug 8.

The electric connector 20 of the present invention comprises an electricinsulating body, which defines a plurality of housings 21, each carryinga binding post 22, which receives and affixes respective wires of thecoil winding 7, said electric insulating body carrying contactterminals, electrically connected to the binding posts 22, and whichwill be connected to the power inlet plug 8 of the shell 1 by respectiveconductors 30, such as for example a conventional wiring, having a firstend 31, for connecting the electric connector 20 of the presentinvention, and a second end 32, for connecting the power inlet plug 8 ofthe compressor.

The electric connector 20 of the present invention further comprises,carried by its electric insulating body, for example incorporated orretained therein, at least one fixing means 23 to be fitted, for exampleby interference, into a retaining bore 11 provided in the stack oflaminations 6 of the stator, in order to be immobilized in relation tothe latter, when introduced into said retaining bore 11.

According to a way of carrying out the invention, the retaining bore 11is a bore made during manufacture, already existing in the stack oflaminations 6 when the present electric connector 20 is installed, andwhich is axially defined in said stack of laminations 6, externally tothe housings that receive the coil windings 7, during production of saidstack of laminations 6, said retaining bore 11 having a certaindiameter, which is previously calculated so as not to interfere with themetallic mass of the stack of laminations 6.

The illustrated fixing means 23 is in the form of a projection,inferiorly extending from a portion of the insulating body of theelectric connector 20 of the present invention, and which is providedwith extensions of external circumferential ribs 24, along a substantialportion of the axial extension of said projection, said externalcircumferential ribs 24 being parallel and aligned to each other andresiliently flexible, in order to be introduced into the retaining bore11. The external circumferential ribs 24 define, for the fixing means23, a diameter that is superior to that of the retaining bore 11, inorder that, after introducing the projection inside the retaining bore11, the efforts to remove said projection will require a modification,in the angular positioning of the external circumferential ribs 24,which surpasses the diameter of the retaining bore 11, thus immobilizingthe present electric connector 20 in relation to the stator.

According to the present invention, the electric connector 20 presents,carried by the electric insulating body, a support stop 25, angularlyprojecting from a rear portion of said insulating body, and which willbe seated on an adjacent portion of the coil windings 7 of the stator,upon fixation of the present electric connector 20 to the stack oflaminations 6 of said stator, said support stop 25 being, for example,fastened to said coil windings 7 upon fastening of the latter.

The support stop 25 is a constructive option, which allows the presentelectric connector 20 to be more safely retained to the stator, andwhich, even though being fastened to the coil windings 7 of the stator,only suppresses two points of the fastening thereof, which points areused for fastening said electric connector 20 to the stator.

The electric insulating body of the present electric connector 20further has at least one front flange 26, defining a guide forpositioning the connector in relation to the stack of laminations 6, andwhich will be seated against an adjacent external wall portion of thestack of laminations 6 of said stator.

According to the illustrations, the insulating body of the electricconnector 20 of the present invention defines, close to the housings 21that receive the binding posts 22, the electric contact terminals, whichconnect the electric terminals of the first end 31 of the electricconductor 30 to be connected to the power inlet plug 8 of the shell 1 ofthe compressor. According to the illustrations, the housings 21 forcontacting the present electric insulating body are of the type havingan upper inlet 27 with a “V” profile, whose vortex portion opens to acradle 28, which receives a wire portion of the coil winding 7,retaining said wire portion and avoiding movement thereof, as well asavoiding possible ruptures due to fatigue resulting from vibrations ofthe compressor during operation thereof.

1. A device comprising: a motor of a hermetic compressor; said motorincluding a stator formed by a stack of laminations , which areoverlapping and lodge coil windings a hermetic shell containing saidmotor therein; said shell carrying a power inlet plug for connection toa current supply source; and an electric connector comprising anelectric insulating body, seated against the stack of laminations of thestator, said electric connector further includes: a plurality of bindingposts which receive and affix respective wires from the coil windings;contact terminals, electrically connected to the binding posts and whichare configured to connect to the power inlet plug of the shell, byrespective conductors; at least one fixing means, which is fitted andimmobilized in a retaining bore provided in the stack of laminations ofthe stator, said fixing means is a projection having externalcircumferential ribs; and a support stop coupled to the electricinsulating body, and which is configured to be seated on an adjacentportion of the coil windings.
 2. The device according to claim 1,wherein the insulating body is seated against one of the end laminationsof the stack of laminations of the stator.
 3. The device according toclaim 2, wherein the retaining bore is axially provided in the stack oflaminations of the stator, externally to the coil windings.
 4. Thedevice according to claim 1, wherein the retaining bore presents adiameter smaller than the diameter of the projection containingextensions of the external circumferential ribs.
 5. The device accordingto claim 4, wherein the extensions of the external circumferential ribsare parallel and aligned to each other, and resiliently flexible forintroduction into the retaining bore.
 6. The device according to claim1, wherein the support stop is fastened to the coil windings.
 7. Thedevice according to claim 1, wherein the support stop is a rearprojection of an upper portion of the electric insulating body.
 8. Thedevice according to claim 7, wherein the electric insulating body isprovided with at least one front flange defining a guide to be seatedagainst an adjacent external wall portion of the stack of laminations ofthe stator.